Crops in construction
The news that Make architects has chosen to form the facade of the University of Nottingham’s Sutton Bonington Biosciences building from modular straw bale panels is a reminder of the role crops play in the construction and finishing of buildings.
Some years ago I visited Forbo’s factory in Kirkcaldy on Scotland’s east coast and saw at first hand how linseed oil, wood flour, limestone, jute and other natural materials are used to manufacture linoleum. Ever since I’ve associated the blue haze of flax fields with the material I have on my bathroom floor. This link between agriculture and the built environment is nothing new – no chocolate box image of England would be complete without its timber framed buildings and thatched cottages built with locally grown materials.
The part crops play in construction is important. Potentially they’re sustainable and bring economic benefits to rural areas. What’s more they’re natural, aesthetically pleasing and have often been tried and tested during centuries of use. They offer the chance to improve the viability of agriculture by adding value to existing crops, using waste agricultural materials or developing new crops. Some would argue that the acreage they occupy should be given over to food production although, in reality, the land used is often insufficiently good to sustain ‘conventional’ crops.
As CIRIA’s Crops in Construction Handbook points out, crop based products have the potential to be used in numerous ways including structural framing, insulation, walling, floor coverings and bio-based geotextiles. Most of these materials have a relatively low environmental impact and, at the end of their life, may be disposed of without going to landfill, sometimes by composting.
Innovators are seeing the benefits of developing crop based products. Hemcrete is a relatively new walling material composed of hemp and lime which is increasingly making its mark both with housing and commercial buildings. Hemp is also used as an insulation product, as is wood fibre. Cellulose insulation comes from recycled newspaper (originally wood pulp) while sheep’s wool insulation is decidedly agricultural. As well as being more pleasant to handle than synthetic products, these natural materials are good at absorbing and re-emitting moisture without it affecting either their stability or insulation value.
Make’s Nottingham scheme will result in the UK’s largest straw bale building and the prefabricated modular panels will be locally produced using straw sourced from the University’s own farmland. ModCell has pioneered this building system and has already seen it employed successfully on a ranging of projects from housing to a media centre.
Image credit: ModCell